Castelli's fastest jersey yet features all of the material and design knowledge the brand has honed since its first aero jersey was released in 2006, and it does not disappoint. The Aero Race 6. 0 Full-Zip Jersey is optimized to counteract the drag we as riders cultivate with an aerodynamic fit that delivers wind-slicing capabilities. It's comfortable enough for all-day training sessions, and breathable enough to keep us dry and cool during intense climbs and long haul days. It even receives feedback from Team Sky as a go-to for training.